Book excerpt: Jacobi's polemical tract Concerning the Doctrine of Spinoza in Letters to Herr Moses Mendelssohn propelled him to notoriety in 1785. This work, as well as David Hume on Faith, or Idealism and Realism, Jacobi to Fichte, and the novel Allwill, is included in George di Giovanni's translation. In a comprehensive introductory essay di Giovanni situates Jacobi in the historical and philosophical context of his time, and shows how Jacobi's life and work reflect the tensions inherent in the late Enlightenment.